The Molecular Biophysics Training Grant at Harvard supports a predoctoral training program focused at the interface of the physical and biological sciences. The goal of the program is to provide students with strong undergraduate backgrounds in quantitative sciences (especially physics and mathematics) with broad training in the biophysical, chemical and molecular concepts and techniques that are required to address outstanding problems in biology and biomedical sciences. The training program links a highly interactive group of 46 faculty members from five departments in Harvard's Faculty of Arts and Sciences, the School of Engineering and Applied Sciences, five departments at Harvard Medical School, and four affiliated hospitals. The training program offers a flexible curriculum drawn from courses offered at Harvard, Harvard Medical School, and MIT, and offers research opportunities in a variety of disciplines relevant to molecular biophysics with particular strengths in the areas of structural biology, computational biology, neuroscience, and imaging. In addition to coursework and research activities, the training program sponsors seminars and guest lectures; a student run, student research seminar series; a yearly retreat featuring a poster session and student and faculty talks in the fall semester; a poster session featuring research of program students; a mini- symposium featuring talks by program faculty during the Biophysics Program recruiting weekend in the spring semester; and social events for all trainees. Over the past 24 years, this training program has helped foster a number of new initiatives in graduate training, and has been remarkably successful in promoting collaborative research among its faculty and interdisciplinary training for its students. In this competitive renewal we request support for 16 training slots for students who are affiliated with Harvard's Biophysics Program or who are jointly affiliated with the Harvard Biophysics Program and Medical Engineering and Medical Physics (MEMP) Ph.D. program in the joint Harvard/MIT Health Sciences and Technology initiative (HST). Students will be preferentially funded in their first and second year of graduate studies.